Spray nozzles are used in a multitude of industrial, agricultural, and commercial applications in which it is frequently necessary to remove the spray tip for various reasons, such as inspection and cleaning, replacement of a worn spray tip, or substitution of the spray tip in order to change the spray pattern. It is desirable, therefore, that such nozzle assemblies permit quick and easy tip removal, while ensuring precise tip orientation and sealing characteristics upon replacement. It further is desirable, particulary for many industrial applications, that such nozzle assemblies be as small as possible with maximized strength for high pressure spraying. Various quick disconnect nozzles heretofore have been proposed and manufactured, but many of these nozzles have had sealing problems, or have made replacement of the spray tips relatively difficult or tiresome, or have required precision machining or molding tolerances, or have had bulky or complex designs.
The following prior patents, all of which are assigned to the same assignee as the present application, have been directed to such problems. U.S. Pat. No. 4,185,781, for example, discloses a quick disconnect nozzle wherein a separate "O" ring sealing member and a separate pressure applying spring are utilized. Radial sealing forces are exerted on the "O" ring by virtue of its interposed mounting between outer periphery of the nozzle tip and an inner peripheral wall of the nozzle body. The spring biases the nozzle tip toward its operative position U.S. Pat. No. 4,438,884 discloses a quick disconnect nozzle incorporating a tubular shaped combination seal and pressure exerting member, which eliminates the need for a separate biasing spring. With the elongated sealing member interposed between the end of the spray tip and an internal shoulder of the body, the sealing forces in this instance are axially directed. The nozzle designs of both of the foregoing patents are of the push and turn type, which necessitate manual forcing of the spray tip against the biasing force of the spring or elongated sealing member and then twisting of the nozzle tip into assembled and locked position. While such nozzles must have sufficient length to accommodate the axial spring or tubular sealing member, both designs have lent themselves well to manufacture by traditional machining methods.
U.S. Pat. No. 4,527,745 discloses a quick disconnect nozzle assembly, which has particular applicability for agricultural uses, and which has camming surfaces adapted for drawing the mating nozzle tip and body parts together against an interposed sealing member in response to rotation of the nozzle tip, without the necessity for simultaneous manual axial forcing of the tip against the sealing member. This design uses a short-length, flat sealing gasket and camming lugs which cooperate with camming and locking slots in a tip carrying cap of the nozzle assembly. U.S. Pat. No. 4,738,401 similarly features camming surfaces to draw the nozzle tip and body together while compressing a tubular configured sealing member with only rotational forces being applied to the tip.
The cam operated designs of both of the foregoing patents utilize a detent action for locating the tip in its fully rotated and finally assembled position. In achieving such detent action, the sealing member must be overcompressed, by virtue of the tip being advanced into the nozzle a greater amount than required for effecting the desired sealing pressure, before the lugs can snap into the detents. Disasembly of the nozzle tip similarly requires overcompression of the sealing member in moving the camming lugs to a position that clear the detents, prior to rotating the nozzle tip in a reverse disengaging direction. Since the axial forces against the sealing member are achieved through rotation of the tip, effecting the overcompression requires greater exertion by the installer. The locking and camming lugs also must have sufficient strength to accommodate the transmission of such greater forces. Because of the complexity of the internal camming surfaces, the designs of both of the foregoing patents have been particularly suited for manufacture by high volume plastic molding techniques.
Quick disconnect nozzles have been found to be particularly problem prone when spraying liquids that contain a high percentage of solids. After prolonged usage, even limited evaporation of the liquid may leave a layer of dried solids that coat exposed surfaces and recesses of the nozzle parts. This coating can interfere with removal of the tip if it is deposited on mating cam surfaces or on surfaces with close tolerances which must be moved relative to each other during disassembly. In quick disconnect nozzles that require the nozzle tip to be forced into the nozzle body to overcompress the seal to a detent disengaging position prior to disassembly, this movement of the tip against the seal and out of the detents during disassembly often also necessitates compressing the deposits within the nozzle. When heavy deposits occur, disassembly of the tip by hand may be significantly impeded or prevented. In addition, after removal of the nozzle tip from the nozzle assembly, it frequently is desirable to direct pressurized fluid through the nozzle body in order to clean and flush out any contaminants that have accumulated. With the spray tip removed, however, such flushing with pressurized liquid can cause the sealing members to become dislodged and be forcefully ejected from the nozzle body, making it necessary to locate the sealing members and then replace them.